Caplan's right, of course, that markets generally do a better job rewarding merit than other systems. Still, I fear he underestimates how off-putting this stuff about markets and meritocracy can be to people who otherwise have some sympathies to libertarian ideas. I can tell plenty of anecdotes from my own experience, but here's a great data point: Ed Kilgore's essay on the crackup of the never very strong liberaltarian alliance. Kilgore concedes some tactical value for his fellow liberals in making alliances with libertarians. He even admits to liking some libertarians
Like Arnold Kling, I agree that some of Kilgore's rhetoric about the libertarian movement's secret crypto-racist tendencies is silly. But unlike Kling, I don't want to write off people like this altogether. Even less than perfect liberal allies can be valuable. And at least some of the burden ought to be on us to try to keep them happy. Making an effort to step away from meritocracy-based defenses of markets is a worthwhile start.